Obsessive Compulsive Disorder (OCD) affects approximately 1 in 200 children and the onset of this disorder in childhood is a significant predictor of adult morbidity. To date, psychotherapy trials for youths with OCD have been designed for children 8 years and older and have been based on age-appropriate adaptations of the individual cognitive-behavioral treatment model found to be effective with adults. While preliminary evidence supports the efficacy of this approach during late childhood and adolescence, neither individual treatment nor cognitive therapy is developmentally appropriate options for the early childhood years. To date, no psychotherapy trials have focused specifically on this early childhood period. There are a number of unique features about early childhood onset OCD including developmental stage, symptom picture, and embeddedness in the family that makes treatment considerations for this disorder different from adults, adolescents, or even older children. Family based treatments have been used for other childhood disorders, but not OCD. Interventions for early childhood onset OCD need to be designed to address both developmental considerations and children's strong embeddedness in their family context. The primary aim of the present proposal is to develop and evaluate a short-term, manualized, family-based treatment intervention for Obsessive Compulsive Disorder (OCD) during early childhood (age 5-8 years). This proposal is submitted as an R21 Exploratory/Developmental Grant for Psychosocial Treatment Research in response to (PA-00-094) Early Identification & Treatment of Mental Disorders in Children). This project is designed to be conducted in three stages 1) Development, 2) Pilot Study, and 3) Randomized Control Study. The Manual Development phase will include review by experts. The Pilot Study stage will assess the intervention protocol for feasibility using 6 children. Information and feedback will be used to prepare a revised treatment manual. Additionally, a relaxation Therapy Manual will be tested in a pilot study of 6 children to determine its acceptability as a control treatment for the randomized study. A randomized controlled trial of 30 children, to compare the CBT manual (N=15) to that of the control (Relaxation) manual (N=15), will be completed. At the end of the study, a final revised, comprehensive, manualized treatment protocol would be completed which could be tested in large efficacy and effectiveness studies.